Hello TstyZmbeAssassinX,
Welcome.
I'm sorry your having this problem. You seem to have done all the usual things.
First, do you have mods or cc? If you do, they may be the cause, but, I never use either, so I don't know.
I cannot guarantee this will work, but, may be worth a try. Save your game under a different name so that you can return to it if this does not work. Move everything you do not want to lose into the family inventory (I hope they don't have too much stuff!). Evict the family and place them temporarily into another empty house. (Don't do anything with them.) Use edit town to go into the problem home and see if the chair is still there. As the game usually removes all "rubbish" from an empty home, it should be deleted. If not, see if you can delete the chair this way. Return to the edit town screen, evict your family and replace them in their home.
The only other thing I can think of is to abandon this house, and give them a new home. If you are using an EA created house, you could get a clean copy by starting a new game, copying the house you want to the bin, then abandoning this game. Return to your game and the copy will be in the bin. Delete the bugged house and replace with the new copy. (This will cost your sims some simoleons.
Good luck.
Finally, being very cautious, I would, if the above has worked, do a factory reset to clean any problems which may have developed over time.
